This adjusts also usage of ARGP_LIBRARY to use ARGP_LIBRARIES which is defined
by the FindArgp module, unlike the former one in case it is provided by libc
directly.
Fixes: #167
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
(cherry picked from commit 8f237bde1508b86cb3469901b534933bb4bbd6b5)